#include<iostream>
using namespace std;
int exam4_13()
{
	int n, i;
	cin >> n;
	i = 2;
	while (n%i != 0 && i <= n - 1)
	{
		i++;
	}
	if (i > n - 1)
	{
		cout << "Yes" << endl;
	}
	else
	{
		cout << "no" << endl;
	}
	return 0;
}